The present invention relates to a device for emptying or raking flowable material from a flowable material storage facility comprised of a plurality of bunkers, silos, stock pules etc. With such flowable materials storage faciuties one problem exists in that the different flowabie materials for their mixing in different amounts must be removed from the individual bunkers, silos, stockpiles etc. This can, for example, be the case in coat-powered power plants when for maintaining the thermal power or exhaust gas specifications, coal types of different qualities must be mixed.
From U.S. Pat. No. 3,401,787 a raking device is known which comprises a raking tunnel positioned under the bunkers, silos, stockpiles etc. which includes a movable bunker raking carriage that is moved across a bunker table and comprises a raking wheel which is rotatably supported thereat. The raking wheel moves the flowable material on both sides from the bunker table via a slot provided in the bunker table onto a continuously operating conveyor device positioned below the raking tunnel. In this device, the bunker raking carriage, after completion of a raking assignment at one storage unit, must be moved from one location to another whereby, depending on the size of the storage device, the travel distance of the bunker raking carriage to the next location may be hundreds of meters long. Therefore, the bunker raking carriages complete this travel distance between the individual raking locations at a fast speed.
The necessary relocation of the bunker raking carriage requires that, during passing of bunkers, silos, stockpiles etc. that are not to be raked, the flowable material positioned on the bunker table in the areas not to be raked must not be engaged by the laterally protecting raking wheel because this would result in errors of the desired mixture of flowable materials.
As a solution to this problem U.S. Pat. No. 3,401,787 suggests that the raking arms of the raking wheel are connected thereto in a foldable manner so that during displacement of the bunker raking carriage the raking arms can be retracted from engagement with the flowable material present on the bunker table on either side of the raking wheel. However, this suggestion has the disadvantage that the folding mechanism for the foldable raking arms is prone to break down because of the rough environment in which the bunker raking carriage is operated and that, furthermore, it is hardly possible with respect to machine technological solutions to make the raking arms foldable into the contour of the bunker raking carriage in an economic (inexpensive) manner such that upon displacement of the bunker raking carriage no undesirable amount of flowable material is accidently removed.
In another raking device known from German Patent 568 750, it is thus suggested to use a raking wheel which rakes only at one side and which is displaceable via its drive shaft, coupled with a gear box to the drive motor, so that the raking wheel with a vertical upward movement can be brought into a position out of engagement with the flowable material flowing out of the lateral bunker slots. The bunker raking carriage can thus be moved to a new location with the raking wheel in a lifted position. However, this entails the disadvantage that the rake tunnel must cover the entire raking wheel to prevent flowable material from falling onto the raking wheel, respectively, a corresponding constructive height for displacement of the raking wheel into the lifted position above the bunker table must be provided. Furthermore, it is not ensured that by lifting the raking wheel into a position above the bunker table material will not be entrained.
It is therefore an object of the present invention to improve a device for raking flowable material from a flowable material storage facility such that with a simple and uncomplicated embodiment of the bunker raking carriage with raking wheel a movement of the bunker raking carriage to the required removal location is made possible without entraining flowable material.